Combustion turbine



April 28, 1931. F. HoFMANN coMBUsTloN TURBINE Filed Feb. l5, 1927 I'.Eu-F. lll

Patented Apr. 28d, 1931 .UNITED STATES PATENT OFFICE FRIEDRICH HORMANN',OF MULIIEIM-RUHR GERMANY, AssIGNoR To IIOLZWARTH GAs TURBINE Co., OF sANFRANCISCO, CALIFORNIA, A CORPORATION OE CALIFORNIA CoMBUsTIoN TURBINEApplication led February 15, 1927. Serial No. 168,282.

The invention relates to combustion turbines of the explosion type andmore particularly to the scavenging systems thereof. In Vsuch turbinesthe products of combustion remaining in the combustion chambers afterthe explosions have taken place, must be removed therefrom by scavengingair prior to the admission of new fuel charges into said combustionchambers. This scavenging air, in addition to its other functions,serves also to cool the nozzle valves, the nozzle chambers and thenozzles, and indirectly the blades, of the turbines in question. Fromthe standpoint of economy it is desirable to create the necessary volumeof suchscavengdening its limits, Fig. 1 is a diagrammatc sectional viewof a combustion chamber with the invention embodied therein Fig. 2.illustrates a modified form of the invention; Fig. 3 is a furthermodificationwhich differs from Fig. 2 in the means provided fordirecting a moistening agentinto the body of scavenging air; Fig .4shows another embodiment of the invention employing a Venturi tubewhereby a m'oistening Huid is sucked up by the. scavenging air as itflows into the charging valve; and Fig. 5 is a section on an enlargedscale hrough the scavenging air valve shown' in ig. 1.v

Referring more particularly toFig. 1 of the drawings 10 representsa-conventional explosion chamber of a combustion turbine,-

which chamber at .one end communicates with the nozzle chamber 11terminating in a nozzle 12 located in operative proXimi-ty tothe blades13 of the rotor 14 customarily forming part of such combustion turbines.

Ing air with'the least expense of power, while technicallyit is mostdesirable to increase to The communication between the combustionchamber-10 and the nozzle chamber 11 is controlled by means of-a nozzlevalve 15 operated in any usual and conventional manner.

At its opposite end the combustion chamber 10 is provided with an inletvalve 16 for controlling the admission ,of scavenging air into theexplosion chamber whereby the latter is scavenged and the products ofcombustion remaining after an explosion has taken place, are expelledtherefrom. The valve 16 is connected by means of a pipe 17 with a sourceof air under pressure. The valve 16 shown in Figs. l and 5 may behydraulically controlled and to this end the stem b of the valve may beprovided with a piston c slidable within a cylinderd forming anextension of the valve casing a. A spring e is arranged to urge thevalve against its seat 31. A conduit f is adapted to be connectedalternately to a source of Oil under pressure and to an eX- haust spacefor such oil, so that the valve is opened at predetermined instants bythe oil under pressure and closed by the spring upon exhaust of suchoil. As so fardescribed the turbine may be of any usual form andarrangements, the illustration in Fig. lbeing diagrammatic in character;generally speaking, turbines of the class in question include also inletvalves, such as valve 16; for the combustion air and for the fuel, whichvalves are located at the same end of the combustion cham-bei` 10 as thevalve 16. As these valves form no part of the present invention theyhave not been shown in detail; the construction and operation of suchvalves are disclosed, for instance, in the patent to Holz- 'Warth No.877,194. In the form of the invention shown in Figs. l and 5 the seat 31of the valves 16 i-s lin the form of a flanged ring set Into the valvecasing a and provided with apertures 20 (shown more clearly in Fig. 5)which are inclinedl with respect to the axis of the valve-16 and'converge inwardly/towards saidaXis. The arrangement is such that'in itsclosed position the valve 16 covers and thereby closes the exit ends ofsaid apertures 20. The latter at their inlet ends communicate with anannular channel22 formed in the valve casing a and connected by means ibecome mixed with the scavengin valve 16 is opened to admit a current ofscavi of a passage 23 with a pipe` 21 which leads to a'source of supplyof moistening iuid,.such as water or steam. o

.In the operation of the turbine, after an explosion of the fuel mixturehas taken place in the combustion chamber ,10, the inlet enging air intosaid chamber which not only scavenges the latter byexpelling therefromthe products of combustion remaining in the chamber 10 subsequent tosaid explosion, but also serves to exert a cooling action on the' nozzlevalve 15, the nozzle chamber 11, and indirectly the blades 13 of therotor 14. As the valve 16-is opened to admit scavengingv air into thecombustion chamber 10, the exit endsof the apertures 20 will beuncovered and thereby will at the same time admit a supply of moisteningfluid into the combustion chamber. This fluid enters said chamber in theform of jets or sprays which converge toward each other from saidapertures 20 and air. In this way a-supply of moistening uid isintroduced into the combustion chamber 10 into the presence of thescavenging air .therein and becomes mixed with the supply of scavengingair in saidchamber 10, In other words, the scavenging aireithercoincidentally with its entrance into the chamber 10 entrainsmoistening fluid. or approximately at the same timel is moistened withinsaid chamber.

In the form shown in Fig.4 2, the air inlet va1ve .16a controls thecommunication between the interior of the casing a and the entrance endof the combustion chamber 10, the

casing a'being connected by means of a pipe 17a with a source ofscavenging air. The

valve 16a is carried by' a valve stem 6 upon which a piston c ismounted; the latter is `slidable in a cylinder d projecting'axiallyfromthe chamber a, said piston c being acted upon by a spring e tomaintain thavalve 16a in its \closed position and to return it thereto.The cylinder d is connected by means of a pipe f with a. source ofhydraulically orotherwise developed pressure arranged to becomeeii'ective upon the valve piston c at the proper time to shift it to theright in Fig. 2l and to thereby adjust the valve 16a to its openposition. The piston c carries an auxiliary piston 27 a which slidablyextends into an' auxil-` 'iai'y cylinder -28a` connected by means of apipe 21a with a source of moistening fluid either liquid or gaseous.A'tube 19a extends lengthwise of the cylinder-d and hasl its inlet endin connection with the auxiliary cylinder 28a and controlled by theauxiliary piston 27a. At' its opposite end the tube 19a terminatesin anozzle 20a projecting in an vupward'direction at an inclinationtowardythe valve 'seat against which thev valve 16d closes. -l l j In theoperation of the turbine-provided' Cindicated by dotted linesv in Fig.2;- This operation of the valve 16@ occurs subsequent- 1y to theexplosion of a fuel charge in the combustion chamber 10 and serves to'admit a supply of scavenging air to the latter whereby the products ofcombustion, remaining in said chamber, are expelled therefrom. As j thisadjustment of the valve 16-to its open position takes place theauxiliary piston 27a is caused to describe acorrespondlng movement tothe right in-Fig. 2 which is sufficient in extent to uncover the inletend o the tube 19a and to thereby bring said tube into opencommunication with the pipe 21a and consequently with the sourceof'moistening fluid.

As `this occurs the moistening fluid will be expelled from the nozzle20a and will be ejected therefrom in the-form of a jet or spray whichpasses by the-open valve 16a into the combustion chamber 10 and becomesmixed with the scavenging air therein.

In theV form shown in Fig. 3, a tube 196 c'orresponding to the tube 19aof Fig. 2 instead of .terminating in a nozzle such as 20a, communicateswith an annular channel 206 lo-v catedl in close proximity to the seatagainst which the air inlet valve 166 seats itself in its closedposition. The annular channel 206 is provided with apertures g whichproject radially inward and establish communication between the channel206 and the casing a which corresponds to the casing a of Fig. 2.Otherwise the form shown in'Fig. 3 may be constructed and operate in thesame Wag as the form shown in Fig. 2.

fter the valve 166 is opened the inlet end of the tube 196 will beuncovered as in Fig. 2 and moistening fluid will accordingly passthrough the apertures gfin the form of jets or sprays and into thecurrent or scavenging airiowing from the casing a" past the open valve166 into the combustion chamber 10. The apertures g and accordingly thejets of moistening fluid passing inwardly therethrough are located atthe point at which- Athe speed of inflowin current of scavenging to thepreviously mentioned casings a an a and atits other endis connectedbymeans of a pipe 17 6with `a source of scavenging air ing air in.flowing through the under pressure. An injector nozzle 20c extends intothe Venturi tube 31 and is connected by means lof a passage 190 with acollecting vat 2lb arranged to contain a supply of clear water or othersuitable moisteiiing fluid L and connected by means of a pipe,J V21ewith a source of supply of such meistening fluid. A float valve carriedbya float j serves to automatically control the commu-v nication betweenthe pipe' 21e and the interior of the vat 21Zi`whereby a supply of fluidz, is continuously maintained in said vat. A valve 7c is manuallyoperated, for instance by means of a handle l, to. control theconnection between the chamber and the nozzle 200.

A s the air valve 160 in th-is form of the invention is opened to admita supply of scavenging. air to lthe combustion chamber l0 as in theforms previously described, the scavenging air will flow from'the pipe176s through the Venturi tube 31 and'cl'iamber a2 into the chamberlO.The current of scaveng- Venturi tube 31 will develop a suction orejector action in the nozzle 205 and thereby serve to draw themoistening fluid 71. through said nozzle in the form of a spray or jet.In other words, as the scavenging air passes the nozzle 20c it entrainsmoistening fluid 7i issuing from said nozzle.

In all of the arrangements the humiditying or moisten-ing 'of 'thescavenging air, either with clear water, withvaporized water in the formof steam, or with any other suitable `inoistening agent, takes placeeither coincidentally with the introduction of the scavenging air. intothe combustion chamber or at approximately the same time. The moistureentrained in theaforesaid scavenging air causes the development of steamowing to the high temperature of the walls of the explosion chamber. Asin a mixture of gases the pressure of the mixture is equal to the sum ofthe partial or individual pressures of its constituents, the partialpressure of the air is decreased by the development and admixture ofsteam, the total pressure remaining unaffected, whereby an increase inthe volume of the air is caused, se that a smaller quantity ofscavenging air need be employed. The mixture of air and moistening fluidand more particularly the mixture of air and steam develops a muchhigher and more efficient cooling action than air alone. The moisteningfluid instead of being added to the air in the form ofpreviously createdsteam or vapor, may' also, in part, comprise cominuted or atomized waterwhich first becomes vaporized as it escapes into the combustion chamberon its -way through the chamber and through the associated elements. Theaddition of water can therefore take place in liquid form or in the formof vapor and may 'occur during the entire period of entrance of. airinto the chamber 10 valve lsaid valve for introducing a or during a partof said period. It may begin for instance after the entrance of thelatter into the said chamber. Other timing arrangements may be adoptedwithout departing from the nature of my invention as set forth in theclaims. By adding the moistening fluid to the scavenging air theformation of scalein the combustion chamber on the associated elementsis reduced and practically done away With. If clean Wateris notavailable fit is desirable to previously remove the scale either whollyor in part. This may be done by using cleared hot water in the turbine,as with a temperature of over 60 the scale for the most part will easilyfall away. When steam is employed it is of advantage to use the exhauststeam of the turbine. f

Various changes in the specific forms shown and described may be madewithin the scope of the claims from the spirit of my invention.

I claim:

" '1. In a combustion turbine of the explotion and expansion of theexplosive charge,

scavenging air into said chamber for scavenging the same, and mea-iiswhereby a liquid without departing i moistening fluid, in the form` ofjets, is introduced into the body of said air for admix` ture therewith.

2. In a combustion turbine of the explo-4.

sion type, the combination chamber, an air conduit for introducingscavenging air into said chamber, an air controlling the admission of.said scavof an explosion enging air to said chamber, eratingcoincidentally with the opening of moistening liquid agent into the bodyof said air for admixture therewith. y

' 3. In a combustion turbine of the explosion type, the combination ofan explosion chamber, an air conduit for introducing scavenging air intosaid chamber, a valve casing connected with a source of moisteningfluid, an annular member in said casing constituting a valve seat andprovided with inwardly converging apertures, an annular channel in saidcasing connected with said apertures and communicating with said sourceof moistening fluid, an air valve cooperating with said seat to controlthe admission of said scavenging air to said chamber and alsocontrolling said apertures for the coincidental admission of moisteningfluid into the body of said scavenging air.

, 4. The improvement in the art of generating power with the aid ofexplosion gases obtained by the successive explosions of combustible4mixtures of fuel and air intermittently charged into a confinedexplosion space, which comprises charging air into and means opsuchspace, after the explosion of a charge therein and the expansion of theresulting combustion gases, to scavenge said space of the residual hotexplosion gases, and substantially simultaneously charging moistureintosuch space andthereby converting such moisture into steam, whereby thequantity ofair necessary to scavenge such space 1s reduced and a greatercooling effect is obtained. In testimony whereof I have hereunto set` myhand. i

FRIEDRICH HOFMANN.

